Rheostat.



PATENTED DBG. 10, 1907.

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m@ n l Hb i controlling devices of the type known as ycircuit cannot beclosed except through the .that means be provided whereby if the regle',and an o ver oad magnet is provided to UNITED sTATEs PATENT oEEroE.

HENRY PRICE BALL, OF NEW YORK, N. Y., ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.-

RHEOSTAT.

Speccation of Letters Patent.

Patented Dec. 1o, 1007'.

manon.. and hmmm 21.1905. sumiso. 292.720.

To dll whom it may concern:

Be it known that I, HENRY PRICE BALL, a citizen 0f the United States,residing at New York, county of New York, State ofl vNew York7 haveinvented certain new-and useful Improvements in Rheostats, of which thefollowing is a specification.

This invention relates to devices forcontrolling electric motor circuitsand has for its object the provisionof a device ofthis character whichwill be protectedv against injury due Yeither to abnormal loadconditions or careless handling and which will be simple of constructionando eration and at the same time thoroughly re iable, safe and durable.

My invention relates more specifically to starting rlieostats in which asufficient-resistance is included vin series with the motor at startingto prevent a dangerous rush of current, resistance being lually cut outas the motor s )eeds up unter it is finally shortcircuited. n devices ofthis character it is essential that provision be made whereby theprotecting resistance. It is also desirable sistance is cut out toorapidly so as to endanger the motor andthe starting resistance, thecircuit will be opened and it will be necessary to return thecontrolling armto starting position before it can beagain closed.

In carrying out my invention I provide a controlling arm ada vted forsliding engage-` ment with a series o contact studs, said con trollingarmbeing pivoted Aso as to move in a plane at right angles to the planeof the contacts so that the circuit may be broken at any contact withoutpassing over the other contacts. This controlling arm I connect with aeontrollin Y handle by means of a tognockout the tog fle an( allow thecontrolling arm, which is iased .to open position, to Vbreak thecircuit. A no-voltage magnet is also pro vided and is so arranged as toact upon a projection of the operating handle to hold the arm in operatiposition. Uponfailure of volta e the hand e is released and the circuitbro en. I also provide means whereby the circuit when once it openedcannot be closed without movin the controlling arm to the startingposition iut which permits the/ opening of the circuit in any positlon.

My invention further consists in the 'feaN` tures of construction andthe arrangement and combination of elements hereinafter set forth andparticularly pointed out in the claims annexed to and forming a part ofthis ap lication.

n the drawings illustrating one embodiment of my invention, Figure 1 isa plan view of the device; F 2 is a side elevation of the same, part ofthe base being broken away; Fig. 3 is a similar view showing theposition of the parts when the circuit is broken; and Fig. 4 is adiagram of circuits.

Referring to the drawingI 10 is an insulating base of slate or soapstoneprovided with a series of contact plates or studs 11 arranged inthe areof a circle and forming termin als of' a starting resistance 12. Mountedwithin' the hase and concentric with the studs 11 is a circular metalliceasing 13 hav'- ing a supportingl flangel 14 which rests upon the base.A eo lar 15 is secured to the flange 14 and base 10-by means of bolts16, ther/zontacting faces of the arts 14 and 15 being cut away so as toaffor a bearing for flange 17 of sleeve 18. The controlling a 19 ispivotedat 20 in brackets' 21 of sleeve 18 and is spring-pressed in theposition shown in Fig.

3 an 1n dotted lines in Fig. 2 by means of the spring 22. The arm 19 ispreferably in the form of a bell crank lever, one end of which isprovidedwith an engaging surface or brush 23 for engaging the contactstuds, the' other end being connected with anjex'tenn sion 24 of theoperating handle 25 b* means of the links 26 and 27 ,forming a togg e.The handle 25 is pivotedin a bracket 280i the sleeve 18 arrangeddiametrically opposite to the brackets 21. The handle 25 is also)rovided with a circular extension 29 extent ing in proximity tothesleeve 1S so as to be un( er the control of the magnet- 3() within thesleeve and concentric therewith. Directly underthis magnet is a secondn'iagnet 31 within the casing 13. These magnets areconcentricallv'arrangeil and a single core 32 having au enlarged head 33on the underside` op osite tothe toggle joint when the lconf4 tro lingarm is down in engagement with the CII contact studs 11, as shown infull lines in Fig. 2. A latch 35A pivoted to the operating handle isspring-pressed toward the collar 15 by means of a spring 36 so as toengage a flange 37 thereon. This iiari'ge extendsonly a portion of thedistance around the collar, as shown in Fig. 1 and is slotted at 38 so aadmit the latch 35.

The operation of my device will be clearly understood from the foregoing-description from which it will be seen that the controlling arm 19 isnormally biased away from the contact studs and is forced vinto contacttherewith by means of the handle 25. With the parts in the positionshown in Fig. 3, the circuit is broken and the latch 35 is in engagementwith the liange 37 so as to hold the operatinghandle and hence thecontrolling arm in the position shown. The controlling arm cannot,therefore, be forced into erigagement with the studs until it is turnedto the left from the position shown in Fig. 1, sufficieritly to allowthe latch 35 to pass through the slot 38. This will be the startingposition of the rli'eostat. When this point is reached the handle may bedrawn up and the toggle being straight, the operating arm will lbemoved. against the tension of thespring 22. As soon as contact is madebetween the arm and the` studs the magnet 30 is energized and its core30 attracts the extension 29 lof the operating handle, as shown in Fig.-

2. The controlling arm may now be moved along tothe right by means ofthe handle to cut out resistance.` At any position of the controllingarm, should the load become eX- cessive, dilo to too rapid movment ofthe arm .or to other causes or when the arm `has reached theshort-circuited position on the last stud, the overload magnet 31willattract the head 33 against the tension of'the spring 34 andtheprojecting end 32 'will' strike the toggle joint and break the sameallowing the controlling arm to take the position shown mdotted lines inFig. 2. Likewise upon failure of voltage from any cause or-with the armin any position, the rio-voltage magnet 30 will release the extensionY29 of the operating handle and allow the parts to assume the positionshown in Fig. 3; In either case, after the circuit has beenbroken, itwill be impossible, as before stated, to again close the circu'ituntilthe' arm has been moved to starting position Withthe operating handleopposite the'slot 38.

The arrangement ofthe circuits is shown in Fig. 4 and is extremelysimple. In the arrangement shown the magnet 31 is arranged in serieswith the starting resistance and the armature so that 'When the starting'arm is moved on to the first stud, current passes from a line at Lthrough the magnet coil 31, controlling arm 19, resistance 12, conductor39 to armature A and back` to line 6e at Ll, theicurrent to the shuntfield passing "a rheostat which it is impossible to destroy from thepivotalpoint of the controlling arm at 4]. through thc magnet 30 andlield l" back I to line.

It will thus he seen that .l have provided either by improper handlingor from overloads due to other causes. The opening of the circuitthrough the cntrolling arm is independent of the operating handle sothat on any stud for too long a time, the circuit will be broken withoutmovement` of the handle., It vill then he necessary that the arm beagain moved to starting position before the circuit can be closed.

While I have described a specific construction and arrangement of parts,it should be understood that I do not limit my invention thereto, sincevarious modifications may be made therein without departing from thespirit ofiny invention, the scope of which is set forth in the claimshereto annexed.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,-

1. A rheostat comprising a series of contacts, a `controlling armmounted for sliding engagement therewithto vary the resistance,

and means for breaking the circuit at any of said contacts bydisengaging said arm therefrom upon the occurrence of underload or 9overload conditions.

2. A starting rheostat comprising a series of contacts, a controllingarm mounted to successively engage the same to vary the resistance,means for disengaging said arm 100 from any of said contacts toY breakthe circuit upon. thel occurrence oi underload or overload conditions,and, means for prevent- Airiga rengagement until the arm is brought tostarting position.

3. A starting rheostat comprising a series of contacts, a controllingarm adapted for sliding engagement with said contacts but biasedtherefrom and pivoted for movement in a plane at an angle to the planeof said 110 contacts, and means for preventing engage- .mentbetweerisaid arm andsaid contacts until the former is' moved to the startingposition. f

4. A rheostat comprising aseries of con- 115 tacts, a controlling armadapted for sliding yengagement Awith said contactsbut biased therefromand pivoted for'movernent in a plane at an angle to the plane of saidcontacts, means for holding said arm in engage- 120 meritwithsaidcontacts during normal operation, and means for releasing thesame in any position upon the occurrence of underload or overloadconditions.

5. A starting rheostat comprising a series 125 contacts, means forpreventing engagementV 130 87eme :e former is moved to the startingposition, 'i means ,for releasing the same in any' position upon theoccurrence of underload or overload conditions.v v

6. A starting rheostat comprising a series olt rv-intacts, a controlling'arm adapted for slidinff engagement with said. contacts but Ui sertherefrom and pivoted lfor movement in a piano at an an le to the laneof said contacts, means for olding said arm in enelnent with saidcontacts during normal operation, means for releasing the Vsame in air-Yposition upon vthe occurrence of underpreventing engagementy betweensaid arm and said contacts until the former is moved to the startingposition.

7. A rheostat comprising a series of contacts, a controlling arm plvotedfor movement in a plane at an angle to the plane of said contacts andadapted to successively engage the same but biased from the contacts',means for holding said arm in engagement with said cont-acts duringnormal operaLion, an operating handle, and inc-ins for releasing saidarm independently of said handle.

A rheostat .comprising a series of con-- tacts, a controlling armadapted for sliding engagement with said contacts but biased th ,reronnmoans forholding said arm in en gageinent with said contacts duringrnormal operation, an operating handle, and an electromag. device forreleasing said arm independcntly of' said handle.

f). A rlioostat comprising a series of contacts, a f ntrolling armtherefor', an operating handie, toggle connections between said arm andsaid handle and means for opening thc circuit upon the occurrence ofabnormal conditions therein.

1li'. A rire stat comprising a series of conrolling arm therefor biasedto t position, an operating handle, inectons between said arm and ile,and a rio-volta c magnet acting l. handle to hold arm in opera rheostatcomprising a of con- -ntrolling arm adapted for sliding with said-contacts but biased Y, au operating handle, toggle conM vload oroverload conditions, and means for nections between said arm and saidliandle for holding the former in engagement with4 $5 said contact-sduring normal operation, and an overload device acting lupon said toggleto release said. arm. y

12. A rheostat comprising a ries of contacts, a' controlling varmtherefor biased to open circuit position, an operating handle, toggleconnections between said arm and said handle, a no-voltagc magnet actingupon `said handle to hold said arm in operative position, and anoverload device acting upon said toggle to release said arm.

i3. A starting rheostat comprising a series of contacts, a controllingarm therefor biased to open circuit position, an operating handle, togrle connections betweenY said arm and sai hadle,.a 11o-voltage magnetacting upon said handle to hold said arm in closed circuit position, andmeans for preventing movcmen t of the arm to the closed circuit positionuntil it has been moved tc the starting positionv f 14. A rheostat comrising a series of contacts, a movable mein er mounted to rotate in aplane parallel to the plane vof the contacts, a controliing clementpivoted thereto for movement in a plane at an angle to the plane of thecontacts, a similarly pivoted operating handle, liek connections betweensaid han ie and snif "rm, and an electromagneiic device i holding saidarm in operative position and or rceasing the saine upon the occurrenceoi undcrload conditions.

15. A rheostat comprising a series of contacts, a movable inem.' mountedto rotate in a plano pa l to the piane of t contacts, a conxfsolllvelement pivotod thereto for movement in a piano ai. an angle to thesirniiarliT pivoted op- 4 o, tom `Vrmnections between said handle and il zu'in, and elcctromagnotie dcvic im' holding said arm in operan tiveposition ai i Vor rol asing the same upon 'the occurrence oi nndcr'oodor overload con ditions.

ln witness 3reni i ve hereunto set my hand. this 15in day rm december.IQCS.

plane oi the contacts, :i

crating han.v

